Vitamin B2, commonly called riboflavin, is one of eight water-soluble B vitamins. Like its close relative vitamin B1 (thiamine), riboflavin plays a crucial role in certain metabolic reactions, particularly the conversion of carbohydrates into sugar, which is "burned" to produce energy. Together, the eight B vitamins, often referred to as B complex vitamins, are also essential in the breakdown of fats and protein. In addition, B complex vitamins play an important role in maintaining muscle tone along the lining of the digestive tract and promoting the health of the nervous system, skin, hair, eyes, mouth, and liver.

In addition to producing energy for the body, riboflavin also works as an antioxidant by scavenging damaging particles in the body known as free radicals. These particles occur naturally in the body but can damage cell membranes, interact with genetic material, and possibly contribute to the aging process as well as the development of a number of health conditions such as heart disease and cancer. Antioxidants such as riboflavin can neutralize free radicals and may reduce or even help prevent some of the damage they cause.

Unlike other B vitamins, riboflavin is not found in many foods, so the most common cause of deficiency is lack of dietary intake, especially in the elderly. Symptoms of riboflavin deficiency include fatigue; slowed growth; digestive problems; cracks and sores around the corners of the mouth; swollen magenta tongue; eye fatigue; soreness of the lips, mouth and tongue; and sensitivity to light. Riboflavin is an important nutrient in the prevention of headache and some visual disturbances, particularly cataracts.

Cataracts
Dietary and supplemental vitamin B2, along with other nutrients is important for normal vision and prevention of cataracts (damage to the lens of the eye which can lead to cloudy vision). In fact, people with plenty of protein and vitamins A, B1, B2, and B3 (niacin) in their diet are less likely to develop cataracts. Plus, taking additional supplements of vitamins C, E, and B complex (particularly the B1, B2, B9 [folic acid], and B12 [cobalamin] in the complex ) may further protect the lens of your eyes from developing cataracts. (Note: no more than 10 mg per day of riboflavin should be used because levels above that could actually promote damage to the lens from the sun.)

Migraine Headache
For many migraine sufferers, taking riboflavin regularly may help decrease the frequency and shorten the duration of migraine headaches. It is not clear how riboflavin compares to conventional medications used to prevent migraine headaches, however.

Burns
It is especially important for people who have sustained serious burns to obtain adequate amounts of nutrients in their daily diet. When skin is burned, a substantial percentage of micronutrients may be lost. This increases the risk for infection, slows the healing process, prolongs the hospital stay, and even increases the risk of death. Although it is unclear which micronutrients are most beneficial for people with burns, many studies suggest that a multivitamin including the B complex vitamins may aid in the recovery process.

Eating Disorders
Levels of important nutrients are often quite low in people with anorexia or bulimia. At least 20% of people with anorexia admitted to a hospital for treatment are deficient in vitamins B2 and B6 (pyridoxine). Some research information suggests that as many as 33% of those with an eating disorder could be deficient in vitamins B2 and B6. Dietary changes alone, without additional supplements, can often bring vitamin B levels back to normal. However, extra B2 and B6 may be required (which will be determined by your doctor or nutritionist). Plus, B-complex vitamins may help alleviate stress and reduce symptoms of depression, frequently associated with eating disorders.

Anemia
Children with sickle-cell anemia (a blood disorder characterized by abnormally shaped red blood cells) tend to have lower levels of certain antioxidants including riboflavin. Studies also suggest that riboflavin supplementation may improve iron deficiency anemia by enhancing the response to iron.

Other
Low levels of riboflavin in the diet and/or riboflavin deficiency has been associated with rheumatoid arthritis, carpal tunnel syndrome, Crohn's disease, colon cancer, atherosclerotic heart disease, and multiple sclerosis. It is not clear, however, whether increased riboflavin in the diet or riboflavin supplements would help protect against any of these conditions except for, perhaps, carpal tunnel syndrome. There have been a couple of reports in the medical literature about a few individuals with carpal tunnel syndrome and low levels of riboflavin experiencing improvement in their symptoms by taking this B vitamin. More research for each of these conditions is needed.

The best sources of riboflavin include brewer's yeast, almonds, organ meats, whole grains, wheat germ, wild rice, mushrooms, soybeans, milk, yogurt, eggs, broccoli, brussel sprouts, and spinach. Flours and cereals are often fortified with riboflavin.

Riboflavin is destroyed by light; therefore, items should be stored away from the light to protect their riboflavin content. This is the reason that many dairy companies switched from glass milk bottles to cartons and opaque containers.

While riboflavin is not destroyed by heat, it can be lost in water when foods are boiled or soaked.

Riboflavin is generally included in multivitamin preparations and in B-complex vitamins, and comes individually in 25-, 50-, and 100-mg tablets.

As with all medicines, check with a healthcare provider before giving riboflavin supplements to a child.

Daily recommendations for dietary riboflavin are listed below.

Pediatric

• Infants birth to 6 months: 0.3 mg (adequate intake)
• Infants 7 to 12 months: 0.4 mg (adequate intake)
• Children 1 to 3 years: 0.5 mg (RDA)
• Children 4 to 8 years: 0.6 mg (RDA)
• Children 9 to 13 years: 0.9 mg (RDA)
• Males 14 to 18 years: 1.3 mg (RDA)
• Females 14 to 18 years: 1 mg (RDA)

Adult

• Males 19 years and older: 1.3 mg (RDA)
• Females 19 years and older: 1.1 mg (RDA)
• Pregnant females: 1.4 mg (RDA)
• Breastfeeding females: 1.6 mg (RDA)

People who do not eat a balanced diet every day would likely benefit from taking a multivitamin and mineral complex on a daily basis A good rule of thumb when selecting a multivitamin is to look for one that includes 100% to 300 % of the Daily Value for all essential vitamins and minerals. If you decide to increase the amount of a particular nutrient make sure you know the safe supplemental range and any contraindications. It is wise to check with a knowledgeable health care provider if you are considering nutrient supplements doses higher than 300 % Daily Value.

Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable healthcare provider.

Absorption of Vitamin B2 is best when it is taken with meals.

Riboflavin does not appear to cause any serious side effects. Possible reactions to very high doses may include itching, numbness, burning or prickling sensations, and sensitivity to light.

Taking any one of the B complex vitamins for a long period of time can result in an imbalance of other important B vitamins. For this reason, it is generally important to take a B complex vitamin with any single B vitamin.

If you are currently being treated with any of the following medications, you should not use vitamin B2 supplements without first talking to your healthcare provider.

Antibiotics, Tetracycline
Riboflavin should not be taken at the same time as the antibiotic tetracycline because it interferes with the absorption and effectiveness of this medication. Riboflavin either alone or in combination with other B vitamins should be taken at different times from tetracycline. (All vitamin B complex supplements act in this way and should therefore be taken at different times from tetracycline.)

In addition, long-term use of antibiotics can deplete vitamin B levels in the body, particularly B2, B9, B12, and vitamin H (biotin), which is considered part of the B complex.

Antidepressant Medications
Tricyclic antidepressants (such as imipramine, desimpramine, amitriptyline, and nortriptyline) also reduce levels of riboflavin in the body. Taking riboflavin may improve levels of the vitamin and improve the effectiveness of these antidepressants, especially in elderly patients.

Anti-malarial Medications
Riboflavin may reduce the effectiveness of anti-malarial medications such as chloroquine and mefloquine.

Antipsychotic Medications
Antipsychotic medications called phenothiazines (such as chlorpromazine) may lower riboflavin levels.

Birth Control Medications
Poor dietary habits in combination with birth control medications can interfere with the body's ability to use riboflavin.

Doxorubicin
In the presence of daylight, riboflavin may deactivate doxorubicin, a medication used for the treatment of certain cancers. In addition, doxorubicin may deplete levels of riboflavin and, therefore, increased amounts of this nutrient may be recommended during chemotherapy using this drug. Your doctor will guide you on whether this is necessary or not.

Methotrexate
Methotrexate, a medication used to treat cancer, can prevent the body from making riboflavin (as well as other essential vitamins).

Phenytoin
Phenytoin, a medication used to control epileptic seizures, may affect riboflavin levels in children.

Probenecid
This medication used for gout may decrease the absorption of riboflavin from the digestive tract and increase the excretion in the urine.

Selegiline
Similar to its effects on doxorubicin, riboflavin may deactivate selegiline, a medication used to treat Parkinson's disease, in the presence of daylight.

Sulfa-containing Medications
Riboflavin may reduce the effectiveness of sulfa-containing medications, such as certain antibiotics (for example, trimethoprim-sulfamethoxazole) used to treat bacterial infections.

In addition, as stated earlier, long-term use of antibiotics can deplete vitamin B levels in the body, particularly B2, B9, B12, and vitamin H (biotin), which is considered part of the B complex. 

Thiazide Diuretics
Diuretics that belong to a class known as thiazides, such as hydrochlorothiazide, may increase the loss of riboflavin in the urine.

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